Relationship between progression of visual field damage and choroidal thickness in eyes with normal-tension glaucoma

Background: To measure choroidal thickness in normal eyes and in patients with normal-tension glaucoma using enhanced depth imaging optical coherence tomography and evaluate the association between choroidal thickness and progression of visual field damage. Design: Cross-sectional comparative study. Participants: A total of 62 eyes of 62 normal subjects and 45 eyes of 45 normal-tension glaucoma patients were examined. Methods: The choroid was measured at the fovea and 3mm nasal and temporal from the fovea. In the separate study, both eyes of the patients with normal-tension glaucoma were included in the analyses. Visual fields were measured with automated perimetry. Changes in mean deviation per year (dB/year), that is, mean deviation slope, were calculated. Main Outcome Measures: Difference in the choroidal thickness between the normal subjects and the patients with normal-tension glaucoma. The relationship between mean deviation slope and the choroidal thickness in eyes with normal-tension glaucoma was analysed. Results: Compared with normal subjects, the choroidal thickness was significantly thinner in eyes with normal-tension glaucoma at 3mm nasal from the fovea (P=0.02). There was a significant correlation between the choroidal thickness at 3mm nasal from the fovea and the mean deviation slope (Pearson's r=0.413; P<0.001). Conclusion: The decrease in the thickness of the choroid at 3mm nasal from the fovea in eyes with normal-tension glaucoma may be associated with progressive visual field loss. Thus, choroidal abnormalities may play a role in the pathogenesis of normal-tension glaucoma.